CHEM 1 naming · trends · stoichiometry · calculator

Significant figures

  1. Nonzero digits always count.
  2. A zero between nonzero digits counts.
  3. Leading zeros never count.
  4. Trailing zeros count when a decimal point is written.
  5. Trailing zeros with no decimal are ambiguous. Use scientific notation.
  6. Counts, and factors marked exact, do not limit a result.
× ÷fewest sig figs
+ −fewest decimal places
log / pHdecimals = sig figs

Round 5 and up. Round only the final answer, and keep one extra digit in the middle of a problem. The calculator on the right follows these rules.

Constants

Use the digits your class prints if they differ. Nₐ and R here are the usual Chem 1 set. STP in most Chem 1 classes is still 0 °C and 1 atm.

Reference tables

Calculator

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Scientific is the full calculator. Data is where a list of numbers gets a chart.